Japan's PM Shinzo Abe said his country would "never tolerate" such "dangerous provocative action".
"If North Korea continues to walk down this path, it has no bright future," he said in a statement.
US Secretary of State Rex Tillerson also condemned the launch, which contravened UN sanctions.
He put the burden of response on China and Russia, nuclear-armed North Korea's main economic partners, saying they "must indicate their intolerance for these reckless missile launches by taking direct actions of their own".
Minutes after the launch, South Korea fired two ballistic missiles into the sea in a simulated strike on North Korea, reported Yonhap news agency.
President Moon Jae-in held an emergency meeting of his national security council, where he said that dialogue with the North was "impossible in a situation like this", reported Yonhap news agency.
Mr Moon was elected earlier this year after campaigning partly on conducting more dialogue with Pyongyang.
The South Korean military said the latest launch - the first since sanctions were tightened this week - took place from the Sunan airfield north of Pyongyang just before 07:00 local time (22:00 GMT on Thursday).
As with the last launch, it flew over Japan's northern Hokkaido island before splashing down in the Pacific Ocean.
Sirens sounded across the region and text message alerts were sent out warning people to take cover.
According to the initial estimates, the missile flew considerably higher and further than the one fired on 29 August, which Pyongyang had warned was only "the first step" in its military operations in the Pacific.
Observers said it was likely an intermediate range ballistic missile (IRBM), though Japanese officials said there was still a possibility it had been an intercontinental ballistic missile (ICBM).
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